stress

I'm now trying to find a good way to create the stress for my conlang
But I'd want it to be natural AND regular
Making it unpredictable would force me to write or to remember it for the
whole words as in English
And I want it to seem natural to not have to think every times "ho no that's
not that one"
So I'd like to ask: Does a regular stress has to depend of its position from
the end of the word? Or from it's beginning (I think like Finnish)?
Is it possible to make it depends from its position from the beggining or
the end of the root? or always on the first, second, third prefix/suffix? or
the last one?
May it depends of the fact that it is a verb, a noun, an adverb..?
It can depends of the word, I know that Romanian stresses the penultima
syllable if the word ends with a syllable and the last one if it ends with a
consonant.
May it depends of something else?
There's a way I've thought of, say me if it sounds natural or if it's too
weird
I stress the first syllable of the word's root with one exception: when the
first syllable's consonant isn't aspirated and that there is one or more
others in the word, the first of them is stressed
The stressed syllable has an higher pitch and is a little longer.
So:
(on verbs, the prefix is always separated by a "-")
we-khate /we'k_hate/ = to love
ze-bana /we'bana/ = to kill
ze-gwedze /ze'g_wedz)e/ = to read
ze-thatane /ze't_hatane/ = to make (someone) born -> (for a doctor or a
mother...)
khate /'khate/ = love
bana /'bana/ = death
thatane /t_hatane/ = life
but
na-tatha /nata't_ha/ = ~there is/are -> a little like the Spanish "Hay" (it
is always conjugated at impersonnal without pronoun)
mathe /ma't_he/ = way, manner
In sentences, the verb conjugates in voice with an infix ("ha", "ho", or
"hi") placed after the first syllable of the root. With that stress method,
I'm sure that it will never be stressed because it's neither the first nor
an aspirated syllable
Also, when two pronouns are next from each other, the first will have it's
first syllable stressed, so they will be pronounced has a word
That way it is regular and easy to remember but does that sounds natural?